[Insight-users] Re: Cellular images : Level Set segmentation

[Luis Ibanez]

Hi XueQuan,

Here are some options that you may want to consider:

1) You can take the Voronoi map image produced by
    the Danielsson or the Maurer distance map filters.

2) For every marker, theshold the voronoi map, so that
    you end up with a mask that has the voronoi region
    corresponding to a single nucleus.

3) Use this binary region to mask the speed image that you
    compute from the gradient magnitude of the original image.
    Pass the resulting masked image as the feature image to
    the level set. In this way you are restricting the level
    set to grow into the voronoi region at most.



About your other question,

If you negate the initial level set, then you can have
it behaving as a shrinking front instead of an expanding
front.


   Regards,



       Luis



-------------------------
qxue at jouy.inra.fr wrote:
> Hello, luis:
>     I have sent an email to the insight-user, but i am not sure whether my
> question is clear. So I send you this letter again.
>     I want to apply the level set method similar to the attachment file.
>     Through DanielssonDistanceMapImageFilter, I have gotten the Voronoi
> segmentation image, but I can not use it to limit the region of level set
> method, for I do not know how to get the area of each Voronoi region.
>     May I get the edges of the every Voronoi segmentaion region getten directly
> from the DanielssonDistanceMapImageFilter.
>     For I want to use the level set method to segmenation nuclei just in its
> Voronoi region exactly.
>     The other question is how to apply a level set method in ITK from outside to
> inside, that is, instead of one or more seeds, may I use the boundary of Voronoi
> and set the velocity is negtive and then the level set is constracted from
> outside to inside, and then stops at the boundary of the nuclei.
>     Thanks,
> XueQuan